async function example() {
    console.log('Start');

    // 异步操作，例如网络请求
    await new Promise(resolve => setTimeout(resolve, 2000));

    console.log('After 2 seconds');

    // 其他同步操作
    console.log('End');
}

example();
console.log('main thread print1');
console.log('main thread print2');
console.log('main thread print3');